3.3.2 Plant defence responses

What do physical defence responses in plants do?

They resist the invasion of micro-organisms.

What are some physical defence responses in plants (3 marks)

Cellulose cell walls- strengthens plant cells, help resist invasion by microorganisms

Tough waxy cuticle on surfaces of leaves is a barrier to pathogen entry

Bark on trees, and a layer of dead cells on the outside of stems, form a protective

What are some chemical defence responses in plants?

Many plants produce antibacterial chemicals that protect them against invading pathogens. Some plants produce poisons that deter herbivores.

How do pathogens leave an infected plant?

If pathogens infect leaves of deciduous trees, the pathogens fall off the tree with the leaves during fall

What are some mechanical adaptations that plants have?

• Thorns and hairs deter animals

• Leaves which droop or curl when touched

• Mimicry to trick animals

Why do plants have mechanical adaptations?

To defend them against herbivores